How long does it take 1 BTU to heat 1 gallon of water?

To heat 1 gallon of water by 1 degree Fahrenheit, it typically requires about 8.34 BTUs. Therefore, the time it takes for 1 BTU to heat 1 gallon of water would depend on the power of the heating source. If, for example, a heater provides 1 BTU per second, it would take approximately 8.34 seconds to raise the temperature of 1 gallon by 1 degree Fahrenheit.